JP2013031634A - Imaging apparatus - Google Patents

Abstract

A tomographic image having a high S / N ratio is obtained by reducing a width in a scanning direction with respect to an array of measurement light.
An image pickup apparatus according to the present invention includes the array in the scanning direction of a scanning unit that scans a plurality of measurement lights based on a detection result of a detection unit that detects an array of the plurality of measurement lights in an inspection object. Adjust.
[Selection] Figure 1

Description

  The present invention relates to an imaging apparatus that acquires a tomographic image of an inspection object.

  In recent years, an optical coherence tomographic imaging apparatus (OCT (optical coherence tomography) apparatus) applying a technique of a low coherence interferometer or a white interferometer has been put into practical use. The OCT apparatus is used to obtain a tomographic image of the fundus retina in the medical field, particularly in the ophthalmic region. Since the OCT apparatus uses the property of light, it can measure with a high resolution of about micrometer which is the order of the wavelength of light. Here, in order to ensure a high signal-to-noise ratio (hereinafter referred to as S / N ratio) of the measurement signal and obtain a high-quality tomographic image, the tomographic image at the same position of the object to be measured is acquired in multiple times. Then, after they are aligned, they are averaged and averaged. Thereby, random noise can be made relatively small, and the SN ratio of the tomographic image is improved. However, when the object to be measured is a living body in the medical field, for example, in the fundus measurement, the human eye, which is a non-measurement object, moves randomly during the measurement, and the measurement image is distorted unless measurement is completed at high speed. It will end up.

  Patent Document 1 discloses a method of speeding up by scanning a measuring light arrayed in a scanning direction using a plurality of light sources, and averaging the data strings of the same measurement location of the measurement object. This method is called tandem scanning. In the clinical field, scanning of various patterns such as a radial scan called a horizontal scan, a vertical scan, and a radial scan is required depending on the medical condition. In order to perform a tandem scan such as a horizontal scan, a vertical scan, and a radial scan with a plurality of light sources, it is necessary to change the angle of the measurement light array on the fundus.

  In order to secure an image with a high S / N ratio by tandem scanning, each measurement light is arranged more parallel to the scanning direction, and the width of the measurement light with respect to the scanning direction created by each measurement light is within a smaller range. Need to fit. In recent years, in order to obtain a higher-resolution image, the diameter of the measurement light is reduced, and imaging is performed with the measurement light having a high NA. With this, the arrangement of the measurement light is smaller than the scanning direction. It is required to be contained within. For this reason, the error between the scanning direction of the optical scanning unit and the arrangement direction of the measurement light must be minute. However, minimizing the error between the scanning direction of the optical scanning unit and the arrangement direction of the measurement light Must be driven to adjust the positional relationship of each measurement light. Therefore, adjustment by experts is necessary.

JP 2010-188114 A

  By the way, the optical scanning unit often shifts due to vibration caused by movement of the OCT apparatus. In addition, when a mechanism for changing the angle of the measurement light array, such as an image rotator, is provided, the image rotator is guided to a predetermined position using a sensor for obtaining the reference position of the image rotator when the OCT apparatus starts up, and the position is set to the origin. As a result, the array angle of the measuring light is adjusted. However, position variations occur when the image rotator is guided to a predetermined position. For this reason, in order to suppress the deviation between the scanning direction and the arrangement direction of the measurement light within a very small range and obtain an image with a high S / N ratio, it is necessary to perform regular maintenance or confirmation and adjustment by an expert when starting up the OCT apparatus. There was a problem.

  Accordingly, an object of the present invention is to reduce the width in the scanning direction with respect to the arrangement of measurement light and obtain a tomographic image with a high SN ratio.

  An imaging apparatus according to the present invention is an imaging apparatus that acquires an image of an inspected object based on a plurality of return lights from the inspected object irradiated with a plurality of measuring lights, and scans the plurality of measuring lights. A scanning unit; a detecting unit that detects an array of the plurality of measurement lights in the object to be inspected; an alignment adjusting unit that adjusts the arrangement of the scanning unit in the scanning direction based on a detection result of the detecting unit; It is characterized by having.

  According to the present invention, it is possible to reduce the width in the scanning direction with respect to the array of measurement light and obtain a tomographic image with a high SN ratio.

It is a figure which shows the structure of the optical coherence tomography apparatus which concerns on 1st and 2nd embodiment. It is a figure which shows the arrangement | sequence of an optical fiber. It is a figure which shows the positional relationship of a light-receiving part and each measurement light. It is a figure for demonstrating how to obtain | require the relationship of the arrangement | sequence of the measurement light with respect to the line sensor L. FIG. It is a figure for demonstrating how to obtain | require with the inclination of the arrangement | sequence of the measurement light with respect to the line sensor L. FIG. FIG. 10 is a diagram for explaining how to obtain the inclination of the X axis of the optical scanning unit 6 with respect to the vertical direction (X axis) of the line sensor L and the positional relationship between each measurement light. FIG. 6 is a diagram for explaining how to determine the inclination of the Y-axis of the optical scanning unit with respect to the line sensor L. It is a figure for demonstrating the correction method of the optical scanning part in the arrangement direction of the measurement light at the time of a tandem scan. It is a figure for demonstrating how to obtain | require the distance of measurement light P1, P2, and P3. It is a figure for demonstrating how to obtain | require the arrangement | sequence of measurement light. It is a figure for demonstrating how to obtain | require the rotation center position of the image rotator. It is a figure for demonstrating how to obtain | require the inclination of X of the optical scanning part with respect to the arrangement | sequence of measurement light. It is a figure which shows the structure of the optical coherence tomography apparatus concerning 3rd and 4th embodiment. It is a figure which shows a detection body. It is a figure for demonstrating how to obtain | require the horizontal belt | band | zone of a detection body, the arrangement | sequence of measurement light, and the inclination of an optical scanning part. It is a figure for demonstrating how to obtain | require the inclination of a vertical belt | band | zone and the scanning direction of the Y-axis of an optical scanning part.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments to which the invention is applied will be described in detail with reference to the accompanying drawings. In addition to the optical coherence tomographic imaging apparatus, the present invention may be anything as long as it is a scanning imaging apparatus (including an endoscope) such as SLO. In addition to the subject's eye, the subject may be the subject's skin or the like.

(First embodiment)
First, a first embodiment of the present invention will be described. FIG. 1A is a diagram illustrating a configuration of an optical coherence tomography apparatus (hereinafter referred to as an OCT apparatus) according to an embodiment of the present invention. The OCT apparatus according to this embodiment includes a light source 1, an optical branching unit 33, a sample arm 1001, a reference arm 1002, a spectrometer 1003, a control unit 23, and a display unit 24. The optical branching unit 33 is connected to the light source 1, the spectroscope 1003, the sample arm 1001, and the reference arm 1002 via optical fibers 32, 34, 39, and 14, respectively. In addition, the OCT apparatus of this embodiment is a structure used as the application example of an optical tomographic imaging apparatus.

  The light source 1 is a light source that emits low-coherence light. Here, the light (light flux) emitted from the light source 1 is propagated to the optical branching unit 33 via the optical fiber 32. The optical branching unit 33 is composed of a fiber coupler or the like. The reference arm 1002 functions as a reference optical system and includes a collimator lens 12 and a reference mirror 13. The reference arm 1002 receives light branched to the optical fiber 39 side by the light branching portion 33 (hereinafter referred to as reference light), and the above-described configuration is provided on the optical path. The reference mirror 13 moves along the optical axis direction in response to the driving force from the driving unit 13a. Thereby, the optical path length of the reference light and the optical path length of the measurement light described later can be matched even for the subject's eyes having different ocular axial lengths. In the present embodiment, the light source 1 has three light sources, and the light branching section 33 and the optical fibers 32, 34, 39, and 14 are provided in correspondence with the three light sources, respectively.

  The sample arm 1001 functions as an imaging optical system, and includes a fiber connection unit 35, an image rotator 2, a collimator lens 5, and an optical scanning unit 6. The light branched to the optical fiber 34 side by the optical branching unit 33 (hereinafter referred to as measurement light) 35a corresponding to each of the optical fibers 34 as shown in FIG. Incident in an arrangement of 35b and 35c. On the optical path, an image rotator 2 for changing the angle of the measurement light array is arranged. When the image rotator 2 is rotated on the optical path by a drive device (not shown), the measurement light is rotated and the angle of the arrangement of the measurement light is changed.

  Measurement light is incident on the optical scanning unit 6 via the collimator lens 5. In addition, the optical scanning part 6 is comprised with the galvanometer mirror which scans a measurement light to the X direction and Y direction arrange | positioned in tandem. The measurement light is scanned from the optical scanning unit 6 of the sample arm 1001 to the fundus 8r of the eye 8 to be examined through the collimator lens 7a and the eyepiece lens 7b. Measurement light between the collimator lens 7a and the eyepiece lens 7b is irradiated in parallel.

  The spectroscope 1003 includes a fiber connection unit 15, a collimator lens 16, a spectroscopic unit 17, an imaging lens 18, and an imaging unit 19. The spectroscope 1003 receives the combined light of the measurement light (return light) and the reference light (reflected light) from the light branching unit 33, and the above-described configuration is provided on the optical path. The spectroscopic unit 17 functions to split light by diffraction. For example, a plurality of diffraction gratings (gratings, prisms, etc.) having dimensions close to the wavelength of light are arranged at equal intervals.

  The imaging unit 19 is composed of a line sensor (imaging elements (CMOS, CCD, etc.) arranged in an array). The imaging unit 19 has detection areas 19a, 19b, and 19c for the light sources 1 on the line sensor, and separately detects incident light signals. Then, the imaging unit 19 generates a signal corresponding to the intensity for each wavelength and outputs the signal to the control unit 23.

  Here, the combined light of the return light from the fundus 8r and the reflected light from the reference mirror 13 has a phase difference. This phase difference is caused by the difference between the optical path length from the optical branching portion 33 to the fundus 8r and the optical path length from the optical branching portion 33 to the reference mirror 13. And since this phase difference changes with wavelengths, an interference fringe arises in the spectral intensity distribution which appears on detection region 19a-c. By obtaining the period of this intensity distribution (interference fringes), the brightness corresponding to the position of the reflecting object can be obtained.

  The control unit 23 includes, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. When the CPU loads a program from the ROM to the RAM and executes it, the control unit 23 controls the operation of each unit in the OCT apparatus. That is, the control unit 23 controls, for example, the image rotator 2, the optical scanning unit 6, the driving unit 13a, the imaging unit 19, and the like. Further, the control unit 23 realizes the functions of the image generation unit 231 and the display control unit 232 by the CPU executing a program stored in the ROM. The image generation unit 231 has a function of analyzing or calculating a signal detected by the imaging unit 19 and generating a tomographic image of the fundus oculi 8r that is an inspection object. The display control unit 232 has a function of causing the display unit 24 to display the fundus tomographic image generated by the image generation unit 231. The method of scanning the measurement light varies depending on the purpose of imaging. For example, a B-scan image can be acquired by scanning the measurement light in the primary direction. In the tandem scan, a B-scan image having a high S / N ratio can be obtained when the image rotator 2 matches the arrangement direction of the measurement light with the scanning direction of the optical scanning unit 6. Note that the image rotator 2 is a configuration serving as an example of an arrangement adjusting unit.

  The mirror 9 between the collimator lens 7a and the eyepiece lens 7b can be driven on the measurement optical path and at a position that does not interfere with the measurement optical path. When scanning the fundus 8r with measurement light, the mirror 9 is driven to a position that does not interfere with the measurement optical path. The light receiving unit 10 detects measurement light and includes a one-dimensional CCD line sensor, a two-dimensional CCD, or the like. The light receiving unit 10 can detect measurement light by arranging the mirror 9 on the measurement optical path.

  The control unit 23 also controls the mirror 9, the light receiving unit 10, and the like. The control unit 23 receives the signal detected by the light receiving unit 10, calculates the irradiation position of the measurement light, and calculates the positional relationship among the image rotator 2, the optical scanning unit 6, and the measurement light. When measuring the arrangement state of measurement light, the mirror 9 is arranged on the measurement optical path. The light emitted from the light source 1 passes through the sample arm 1001 and is irradiated to the light receiving unit 10 as measurement light through the mirror 9.

  FIG. 3 is a diagram illustrating a positional relationship between the light receiving unit 10 and each measurement light. In the example of FIG. 3, a one-dimensional CCD line sensor (hereinafter simply referred to as a line sensor) is used as the light receiving unit 10. In FIG. 3, the straight line portion L is a line sensor, and P1, P2, and P3 arranged on the straight line are measurement light. Here, the longitudinal direction of the line sensor L is defined as the Y axis of the line sensor L, and the vertical direction thereof is defined as the X axis of the line sensor L. When the OCT apparatus is started up and the initial drive of each device is completed, the mirror 9 is on the measurement optical path, and the light receiving unit 10 is irradiated with the measurement light, the center of the line sensor L is designed as shown in FIG. And the center of the array of measurement light coincide with each other.

  The position of the optical scanning unit 6 is a position where measurement light is present with respect to the line sensor L. For example, in a design that does not include each error, when the central measurement light P2 irradiates the negative coordinate side on the line sensor L, the position of the optical scanning unit 6 is also a negative coordinate side position. The scale is the same as that of the line sensor L.

  Further, when the image rotator 2 normally rotates halfway, the light passing therethrough is rotated. For convenience of explanation, the rotation amount of the light is set as the rotation amount of the image rotator 2. Further, the angle of the image rotator 2 when the measurement light array is made horizontal with respect to the line sensor L is 0 °, and the counterclockwise direction is a positive direction.

  First, the control unit 23 checks the relationship of the arrangement of measurement light with respect to the line sensor L. Here, the inclination of the straight line connecting the measurement light P1 and the measurement light P3 that are both ends of the array is defined as the inclination of the array of measurement light. The rotation of the image rotator 2 changes the inclination of the measurement light array. Therefore, the control unit 23 obtains the inclination of a straight line connecting the measurement light P1 and the measurement light P3 with reference to the rotation center position where the image rotator 2 is trying to make the measurement light array horizontal to the line sensor L.

  FIG. 4 is a diagram for explaining how to obtain the relationship of the arrangement of measurement light with respect to the line sensor L. FIG. In the present embodiment, the control unit 23 obtains the measurement light arrangement error and the rotation center position of the image rotator 2 when the image rotator 2 attempts to make the measurement light arrangement horizontal to the line sensor L. .

  As shown in FIG. 4A, the control unit 23 rotates the image rotator 2 to a position where the arrangement of measurement light is horizontal with respect to the line sensor L on the design value, and measures from above the line sensor L. The X axis of the optical scanning unit 6 is shifted in the X axis direction of the line sensor L by a quarter of the interval between the light P1 and the measurement light P3. Here, when the amount by which the X axis of the optical scanning unit 6 is displaced is XS, the position of the optical scanning unit 6 is (XS, 0) in the coordinate system of the line sensor L.

  The amount of rotation of the image rotator 2 here and the amount of movement of the optical scanning unit 6 along the X axis may be determined by design values. Therefore, it is not necessary to consider the attachment error of each of the fiber connection unit 35, the optical scanning unit 6, and the image rotator 2, the error in determining the origin in the rotation direction of the image rotator 2, and the like. Note that the X-axis movement amount of the optical scanning unit 6 is a convenient position for calculation and explanation, and when the image rotator 2 is rotated, the measurement light P1 and the measurement light P3 are Any position that passes through the line sensor L may be used. However, a movement amount in the vicinity of one half of the interval between the measurement light P1 and the measurement light P3 is not preferable in terms of accuracy.

  In this state, the control unit 23 rotates the image rotator 2 and obtains two passing points of the line sensor L for the measurement light P1. Here, a point where the center of the measurement light P1 passes on the line sensor L is a point where the measurement light P1 passes. For example, when the aperture of the measurement light is 40 μm, one pixel of the line sensor L is 5 μm × 5 μm, and the minimum moving amount of the optical scanning unit 6 is 1 μm, the resolution of the optical scanning unit 6 is higher than that of one pixel of the line sensor L. high. Therefore, the point where the light quantity of the measurement light is maximized may be found as the passing point of the line sensor L for the measurement light.

  As one method of obtaining the center position of the measurement light when the measurement light passes on the line sensor L, as shown in FIG. 4B, the control unit 23 detects the measurement light by the line sensor L. Rotate the image rotator 2 until When the line sensor L detects the measurement light, the control unit 23 stops the image rotator 2 there and stores the angle of the image rotator 2. Next, the control unit 23 moves the X axis of the optical scanning unit 6 back and forth, and obtains the X-axis center-of-gravity position XSC from the sum of the light amounts of the pixels receiving the measurement light and the X-axis positions. Next, the control unit 23 moves the X-axis of the optical scanning unit 6 to the X-axis centroid position XSC, and obtains the centroid position YC of the light amount of each pixel received by the line sensor L as the Y-axis center position of the measurement light. . As described above, the center position (XS-XSC, YC) of the measurement light when the measurement light passes over the line sensor L is obtained. After obtaining the passing point (XS-XSC, YC) of the measurement light on the line sensor L in this way, the control unit 23 returns the X axis of the optical scanning unit 6 to the XS position. Hereinafter, the method for obtaining the center position of the measurement light when the measurement light passes through the line sensor L is the same.

Next, as shown in FIG. 4C, the control unit 23, when the center of the measurement light P1 passes over the line sensor L, the amount of the passage of the center of the measurement light P1 over the line sensor L twice. Based on the angles θ ₁ and θ ₂ of the image rotator 2 and the center positions (x ₁ , y ₁ ) and (x ₂ , y ₂ ) of the measurement light P 1 when the measurement light P 1 passes over the line sensor L. The rotation center position rcs of the image rotator 2 when the X axis of the optical scanning unit 6 is moved by XS, and the measurement light when the image rotator 2 tries to level the measurement light array with respect to the line sensor L. The position of P1 is obtained. Note that (x ₁ , y ₁ ) = (XS−XSC, YC). Similarly, the control unit 23 determines the angle of the image rotator 2 when the center of the measurement light P3 passes over the line sensor L, the measurement light P3, and the measurement light P3. Based on the center position of the measurement light P3 when P3 passes over the line sensor L, the rotation center position rcs of the image rotator 2 in the state where the X axis of the optical scanning unit 6 is moved by XS, and the image rotator 2 The position of the measurement light P3 when the arrangement of the measurement light is intended to be horizontal with respect to the line sensor L is obtained.

  Here, using the rotation center position rcs of the image rotator 2, the measurement light is arranged horizontally with respect to the line sensor L, and the measurement light P <b> 1 and P <b> 3 when the X axis of the optical scanning unit 6 is moved XS. The positions are P1a (P1ax, P1ay) and P3a (P3ax, P3ay), respectively. The inclination of the straight line connecting P1a and P3a is the inclination θl of the measurement light array with respect to the line sensor L when the image rotator 2 attempts to level the measurement light array with respect to the line sensor L. That is, if the angle of the image rotator 2 when the image rotator 2 attempts to level the measurement light array with respect to the line sensor L is 0 degree, this inclination is the same as the inclination of the image rotator 2 with respect to the line sensor L. It shows that.

  Next, referring to FIG. 5, the image rotator is considered in consideration of the inclination of the X axis of the optical scanning unit 6 with respect to the vertical direction (X axis) of the line sensor L, the positional relationship between each measurement light, and the positional relationship. A description will be given of how to obtain the inclination of the measurement light array relative to the line sensor L when No. 2 attempts to level the measurement light array relative to the line sensor L.

  First, as shown in FIG. 5A, the control unit 23 rotates the image rotator 2 so that the arrangement of the measurement lights P1 and P3 is perpendicular to the line sensor L. That is, the control unit 23 rotates the image rotator 2 by an angle obtained by subtracting the above θl from 90 ° so that the arrangement of the measurement lights P1 and P3 is perpendicular to the line sensor L. At this time, the drive residual angle α of the image rotator 2 (the rotation angle of the image rotator 2 which is insufficient with respect to the vertical direction (X axis) of the line sensor L) is perpendicular to the arrangement of the measurement lights P1 and P3. It becomes the inclination of the direction (X axis).

As shown in FIG. 5B, the control unit 23 moves the X axis of the optical scanning unit 6 to a position where there is no line sensor L between the measurement lights P1 and P3. Here, the control unit 23 moves the X axis of the optical scanning unit 6 in the direction of the line sensor L. The control unit 23 then positions P3by and P1by on the line sensor L when the center of the measurement light P3 and the center of the measurement light P1 pass the line sensor L, and the X-axis position P3bx of the optical scanning unit 6 at that time. And the inclination θx of the X axis of the optical scanning unit 6 with respect to the vertical direction (X axis) of the line sensor L is obtained from P1bx. Since the drive residual angle α of the image rotator 2 is very small, θx can be obtained by the following equation.
sin (θx) = ((P1by−P3by) ÷ (P1bx−P3bx)) − sinα

  When the control unit 23 scans the optical scanning unit 6 to the X-axis side and obtains the position where the center of the measurement light passes on the line sensor L, the total sum of pixels received at each X-axis position of the optical scanning unit 6 is obtained. The amount of received light is stored. Next, the control unit 23 obtains the position of the center of gravity with respect to the total received light amount, and sets this as the center position of the measurement light on the X-axis side of the optical scanning unit 6. Since the center position is on the line sensor L, the position of the X axis of the line sensor L is zero. Further, the center of gravity of the light quantity of each pixel received by the line sensor L at this position may be set as the center position of the measurement light on the Y axis.

The positional relationship among the measurement lights P1, P2, and P3 is such that the center of the measurement light P1, the center of the measurement light P2, and the center of the measurement light P3 pass through the line sensor L on the coordinate P1b ( 0, P1by), P2b (0, P2by) and P3b (0, P3by), the X-axis positions P1bx, P2bx and P3bx of the optical scanning unit 6 at that time, and the X-axis of the optical scanning unit 6 with respect to the line sensor L And the inclination θx of Incidentally, the drive residual angle α of the image rotator 2 is very small. Accordingly, as shown in FIG. 5C, when it is assumed that the image rotator 2 is driven by the drive residual angle α with the X axis and the Y axis of the optical scanning unit 6 as the position 0 (the image rotator 2 at this time). The positions P1B, P2B, and P3B of the measurement light beams P1, P2, and P3 having a rotation angle of 90 ° −θ1) are obtained by the following equations.
P1B = P1b + (− P1bx × cos θx, P1bx × (sin α + sin θx))
P2B = P2b + (− P2bx × cos θx, P2bx × (sin α + sin θx))
P3B = P3b + (− P3bx × cos θx, P3bx × (sin α + sin θx))

FIG. 5D shows the positional relationship between the line sensor L and the measurement light when the rotation angle of the image rotator 2 is 0 ° and the X axis and Y axis of the optical scanning unit 6 are at the 0 position, and at that time. It shows how to obtain the inclination of the array of measurement light. The rotation center position of the image rotator 2 here is the 0 position of the X axis and the Y axis of the optical scanning unit 6. As described above, the rotation center position when the X axis of the optical scanning unit 6 is moved XS in the X axis direction of the line sensor L is rcs. Therefore, the rotation center position RC of the image rotator 2 when the X axis and the Y axis of the optical scanning unit 6 are at the 0 position is obtained by the following equation.
RC = rcs− (XS × cos θx, XS × sin θx)

  Next, the control unit 23 returns the angle of the image rotator 2 to 0 °. That is, the control unit 23 rotates the image rotator 2 from the position shown in FIG. The positions P1A, P2A, and P3A of the measurement beams P1, P2, and P3 at that time are obtained by the following equation.

  Here, the control part 23 calculates | requires the straight line which passes through the vicinity of the position P1A, P2A, and P3A by the least squares method. The inclination of the line sensor L with respect to the Y axis is the inclination θL of the entire array of measurement light with respect to the line sensor L when the image sensor 2 is rotated to make the array of measurement light horizontal to the line sensor L. As required.

  FIG. 6 is a diagram for explaining how to determine the inclination of the X axis of the optical scanning unit 6 with respect to the vertical direction (X axis) of the line sensor L and the positional relationship between each measurement light. Shows different ways.

  As illustrated in FIG. 6A, the control unit 23 rotates the image rotator 2 to a position when the measurement light array is to be leveled with respect to the line sensor L. Then, the control unit 23 moves the X axis of the optical scanning unit 6 to a position shifted from the line sensor L to one quarter of the interval between the measurement light P1 and the measurement light P3, that is, XS in the X axis direction. At this time, when the image rotator 2 is rotated and the optical scanning unit 6 is driven, the driving amount may be determined based on the design value. It is not necessary to consider the attachment error of each of the fiber connection unit 35, the optical scanning unit 6 and the image rotator 2 and the error in determining the origin in the rotation direction of the image rotator 2. That is, the position of the measurement light P1 and the position of the measurement light P3 at this time are P1a and P3a obtained by the above-described processing.

  The control unit 23 moves the X axis of the optical scanning unit 6 in the direction of the line sensor L. The slope of the straight line connecting the position P1a and the position P1c (0, p1cy) when the center of the measurement light P1 passes the line sensor L is X of the optical scanning unit 6 with respect to the vertical direction (X axis) of the line sensor L. Calculated as the tilt of the axis. In addition, the inclination of the X-axis of the optical scanning unit 6 with respect to the vertical direction (X-axis) of the line sensor L is an inclination of a straight line connecting the position P3a and the position P3c when the center of the measurement light P3 passes through the line sensor L. May be obtained by obtaining. Alternatively, it may be obtained by obtaining the average of the slope of the straight line connecting the position P3a and the position P3c and the slope of the straight line connecting the position P1a and the position P1c described above. In FIG. 6A, the angle of inclination of the X-axis of the optical scanning unit 6 with respect to the vertical direction (X-axis) of the line sensor L is represented by θx as in FIG.

As shown in FIG. 6B, the positional relationship between the measurement lights P1, P2, and P3 is a position P1c (0, 0) on the line sensor L when the centers of the measurement lights P1, P2, and P3 pass through the line sensor L. P1cy), P2c (0, P2cy), and P3c (0, P3cy) and the X-axis positions P1cx, P2cx, and P3cx of the optical scanning unit 6 at that time. The positions P1A, P2A, and P3A of the measurement lights P1, P2, and P3 when the optical scanning unit 6 is set to the position 0 on the X axis are obtained by the following equations.
P1A = P1c− (P1cx × cos θx, P1cx × sin θx)
P2A = P2c− (P2cx × cos θx, P2cx × sin θx)
P3A = P3c− (P3cx × cos θx, P3cx × sin θx)

  As shown in FIG. 6C, the control unit 23 obtains straight lines passing through the positions P1A, P2A, and P3A by the method of least squares or the like. The inclination of the straight line sensor L with respect to the Y-axis is obtained as the inclination θL of the entire measurement light array with respect to the line sensor L when the measurement light array is made to be horizontal with respect to the line sensor L.

Next, the control unit 23 obtains the inclination of the Y axis of the optical scanning unit 6 with respect to the line sensor L. FIG. 7 is a diagram for explaining how to determine the inclination of the Y axis of the optical scanning unit 6 with respect to the line sensor L. FIG. The control unit 23 moves the Y axis of the optical scanning unit 6 to a position where the X axis of the optical scanning unit 6 is set to the 0 position and the measurement light P2 is near the upper portion of the line sensor L. Then, the control unit 23 moves the X axis of the optical scanning unit 6 and searches for a point where the center of the measurement light P2 passes through the line sensor L. From the X-axis position P2ulx of the optical scanning unit 6 when the center of the measurement light P2 passes the line sensor L and the measurement light position P2uly on the line sensor L at that time, the control unit 23 The position Pu1 of the measurement light P2 when the X-axis is at the 0 position is obtained. Here, Pu1 is obtained by the following equation. Θx is a deviation of the X axis of the optical scanning unit 6 with respect to the line sensor L.
Pu1 = (− P2ulx × cos θx, P2uly × sin θx)

Next, the control unit 23 sets the X axis of the optical scanning unit 6 to the 0 position, and moves the Y axis of the optical scanning unit 6 to a position where the measurement light P2 is near the lower part of the line sensor L. Then, the control unit 23 moves the X axis of the optical scanning unit 6 and searches for a point where the center of the measurement light P2 passes through the line sensor L. From the X-axis position P2dlx of the optical scanning unit 6 when the center of the measurement light P2 passes the line sensor L and the measurement light position P2dly on the line sensor L at that time, the control unit 23 The position Pd1 of the measurement light P2 when the X-axis is at the 0 position is obtained. Here, Pd1 is obtained by the following equation. Θx is a deviation of the X axis of the optical scanning unit 6 with respect to the line sensor L.
P2d = (− P2dlx × cos θx, P2dly × sin θx)
The inclination of the straight line connecting the position Pu1 and the position Pd1 is obtained as the inclination angle θy of the Y axis of the optical scanning unit 6 with respect to the line sensor L.

  If the perpendicularity between the X axis and the Y axis of the optical scanning unit 6 has a very small error, and there is no structural shift in the perpendicularity to the X axis, this measurement is omitted with θx = θy. Also good.

  In the present embodiment, the light receiving unit 10 is configured by a one-dimensional CCD line sensor L. However, it may be configured by a two-dimensional CCD, and the optical scanning unit 6 is moved by providing a reference axis in the two-dimensional CCD. The angle error of the axis may be measured to obtain the correction amount for each axis. When a two-dimensional CCD is used, the inclination of the axis of the optical scanning unit 6 with respect to the inclination of the measurement light array can be obtained without driving the measurement light array changing mechanism such as the image rotator 2. In order to obtain the center position of each measurement light using a two-dimensional CCD, the center of gravity of the light quantity of each pixel of the CCD that has received the measurement light may be obtained.

  As described above, in the present embodiment, with reference to the position of the light receiving unit 10 that receives the measurement light, the displacement of the rotation center position of the image rotator 2, the position of the measurement light with respect to the position of the image rotator 2, and the position It is possible to obtain the positional relationship between the angle of the measurement light array obtained from the above and the angle of each axis of the optical scanning unit 6. When the obtained angle and position are different from the design values, the image rotator 2 can correct the angle of the measurement light array. At the same time, the optical scanning unit 6 can correct the rotation center position of the image rotator 2 and the center position of the measurement light array, and the measurement light can be brought close to the design value position.

  The measurement position is based on the coordinates of the light receiving unit 10. Define the relationship between the position where the mirror 9 is not on the measurement optical path and the measurement light is irradiated on the eyepiece 7b and the position where the mirror 9 is on the measurement optical path and the light receiving unit 10 is irradiated with the measurement light, The coordinate system of the light receiving unit 10 is matched with the coordinate system of the eyepiece 7b. Thereby, the measurement position can be corrected to a coordinate position on the fundus 8r.

  FIG. 8 is a diagram for explaining a correction method of the optical scanning unit 6 in the arrangement direction of measurement light at the time of tandem scanning. In the tandem scan, it is necessary to reduce the width of the measurement light with respect to the scanning direction by causing the optical scanning unit 6 to scan in the arrangement direction of the measurement light. For example, as illustrated in FIG. 8A, the control unit 23 moves the image rotator 2 by −θL when attempting to perform a tandem scan vertically. Here, when the drive residual angle θd is generated with respect to −θL due to the drive resolution of the image rotator 2, the measurement light array itself is inclined by θd with respect to the line sensor L. The state in which the drive residual angle θd is generated is a state in which the image rotator 2 is moved only by −θL, but is actually moved only by −θL−θd. Therefore, when the optical scanning unit 6 scans the measurement light so as to be horizontal to θd, a tandem scan with a better SN ratio can be performed. That is, θy−θd is an angle of the Y axis of the optical scanning unit 6 with respect to the arrangement direction of the measurement light, and θx−θd is an angle of the X axis of the optical scanning unit 6 with respect to the vertical direction of the arrangement direction of the measurement light. . Therefore, as shown in FIG. 8A, when the traveling direction of the measuring light is on the positive side of the Y axis, the measuring light of the optical scanning unit 6 can be advanced by a distance l according to the angle of the arrangement direction θd. What is necessary is just to drive the optical scanning part 6 only by the value which multiplied the following correction coefficient with respect to the distance in a X-axis and a Y-axis. When the traveling direction of the measurement light is on the negative side of the Y axis, the value for driving the optical scanning unit 6 takes a negative value. At this time, when θy−θd is a negative value, the X-axis correction coefficient is obtained by multiplying the X-axis correction coefficient by −1.

When the scanning amount of each axis of the optical scanning unit 6 is corrected, the width of each measurement light in the scanning direction of the optical scanning unit 6 can be reduced. This θd is the inclination of the array of measurement light with respect to the line sensor L. Therefore, for example, as shown in FIG. 8B, when it is desired to perform a tandem scan with an angle θT inclined with respect to the line sensor L, the control unit 23 moves the image rotator 2 by θT−θL. If the drive residual angle at that time is θD, and θd is the inclination of the measurement light with respect to the line sensor L, it is expressed as the following equation, and the correction amount of the axis of the optical scanning unit 6 for advancing the measurement light by 1 is Thus, it becomes possible to apply the above correction formula.
θd = θT−θL−θD

  In the above correction equation, when θT is not within ± 45 °, θd is calculated with reference to the vertical direction with respect to the line sensor L, and the correction coefficient can be obtained by exchanging the X axis and the Y axis of the correction equation. That's fine. As shown in FIG. 8C, in the case where the traveling direction of the measurement light is on the positive side of the X axis, in order to advance the measurement light by the distance l in accordance with the angle of the arrangement direction θd, the optical scanning unit 6 is moved to the X axis. It is only necessary to drive a value obtained by multiplying the driving axis between the Y axis and the Y axis by the following correction coefficient. If the traveling direction is the negative side of the X axis, the distance takes a negative value. At this time, when θx−θd becomes a positive value, the X-axis correction coefficient is obtained by multiplying the following Y-axis correction coefficient by −1 to be the Y-axis correction coefficient.

  In this embodiment, the line sensor L is used as a reference for the Y axis, the measurement light array and the error angle of the inclination of each axis of the optical scanning unit 6 are measured, and the correction amount of each driven object is obtained. However, the error of the angle with respect to the reference is measured on the basis of any of the angles of the measurement light array with respect to the reference position of the X-axis, Y-axis of the optical scanning unit 6 or the image rotator 2, and the correction amount of each drive unit is determined. You may ask for it.

  As described above, the position of the measurement light and the measurement based on the position and light amount of the measurement light when the light receiving unit 10 detects the measurement light, the position of the image rotator 2, and the position of the optical scanning unit 6. The positional relationship between the angle of the light array and the scanning angle of the optical scanning unit 6 is obtained.

  From the above positional relationship, the scanning direction of the scanning unit 6 can be adjusted to the arrangement of the measurement light, so that it is not necessary to make a precise adjustment at the time of assembly, and even if a deviation due to a change in time or an impact occurs. The scanning direction of the optical scanning unit with respect to the array of measurement light can be corrected. Therefore, the width of the measurement light with respect to the scanning direction created by each measurement light can be reduced. In addition, since the positional relationship of each measurement light can be measured, it can be seen whether it is deviated from the design value of each measurement light, so by shifting the image for the deviation, each light source can change the data string of the same measurement location of the measurement object. It becomes possible to perform averaging. Thereby, an optical tomographic image with a high S / N ratio can be obtained in the tandem scan.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. FIG.1 (b) is a figure which shows the structure of the OCT apparatus which concerns on the 2nd Embodiment of this invention. Here, as an OCT apparatus according to this embodiment, an imaging apparatus using a Fourier domain optical coherence tomography is taken as an example. The difference from the first embodiment is that there is no image rotator 2 that changes the angle of the measurement light between the fiber connection unit 35 and the optical scanning unit 6. In a clinical site, a tomographic image in the horizontal direction is often taken with respect to the eye. Therefore, here, the arrangement of the measurement light of the fiber connection portion 35 is horizontal and the light source of the optical fiber 34 is shown in FIG. It is fixed with the arrangement | sequence (35a, 35b, 35c) shown to).

  In the present embodiment, the mirror 9 is arranged on the measurement optical path in order to measure the arrangement state of the measurement light. The light emitted from the light source 1 passes through the sample arm 1001 and is irradiated to the light receiving unit 10 as measurement light through the mirror 9. FIG. 11 is a diagram illustrating the positions of the light receiving unit 10 and each measurement light. This embodiment demonstrates the example which comprised the light-receiving part 10 with the one-dimensional line sensor. In FIG. 11, a straight line portion L is a line sensor, and P1, P2, and P3 are measurement lights. Here, the line sensor L is handled as the Y reference axis of the line sensor coordinates. When the apparatus starts up, the initial drive of each device is finished, the mirror 9 is on the measurement optical path, and the light receiving unit 10 is irradiated with the measurement light, as shown in FIG. It is assumed that the center of the measurement light array coincides.

  The position of the optical scanning unit 6 is the position where the measurement light is present with respect to the line sensor L, that is, the optical scanning unit when the design measurement light not including each error irradiates the negative coordinate side on the line sensor L. The position 6 is a minus position. The scale is the same as that of the line sensor L.

  In this embodiment, the arrangement of the measurement light cannot be changed. Accordingly, the alignment of the measurement light P1, P2, and P3 and the inclination angle θx of the X-axis of the optical scanning unit 6 are obtained, and the optical scanning unit 6 is corrected to the inclination of the measurement light array, thereby correcting the inclination of the measurement light array. The scanning direction of the optical scanning unit 6 is adjusted to the same.

  FIG. 12 is a diagram for explaining how to determine the inclination of X of the optical scanning unit with respect to the array of measurement light. The control unit 23 drives the X axis of the optical scanning unit 6 to move it to a position where the line sensor L is not present between the measurement lights P1, P2, and P3. As shown in FIG. 12A, the control unit 23 drives the X axis of the optical scanning unit 6 in the line sensor L direction. The control unit 23 then adjusts the positions P1b, P2b, and P3b on the line sensor when the centers of the measurement lights P1, P2, and P3 pass the line sensor L, and the X-axis position P1bx of the optical scanning unit 6 at that time. P2bx and P3bx are obtained.

When the optical scanning unit 6 scans to the X-axis side and obtains the position where the center of the measurement light passes on the line sensor L, the total of pixels scanned and received at each position on the X-axis of the optical scanning unit 6 is calculated. Remember the amount of light received. Then, the position of the center of gravity with respect to the amount of received light is obtained, and this is set as the center position of measurement light on the X side (the position of X on the line sensor coordinates is 0 because it is on the line sensor L), and the line sensor L receives light at this position. The barycentric position of the light quantity of each pixel may be set as the center position of the Y axis of the measurement light. Here, P1b = (0, P1by); P2b = (0, P2by); P3b = (0, P3by); Taking P1 and P3 separated as measurement light, the arrangement of the measurement lights P1 and P3 The angle θx1 is obtained as the inclination of the X-axis of the optical scanning unit 6 with respect to.
tan (θx1) = (P3by−P1by) ÷ (P3bx−P1bx)

  However, if the θxq is a large value in the vicinity of 10 ° due to the inclination of the optical scanning unit 6 or the like, the error becomes large even with a cos error. Therefore, for example, when the distance between the measurement lights P1 and P3 is 2 mm, if the correction is made with the angle of θx1, the center of the measurement light has a width with respect to the corrected scanning axis by about 5 μm. Depending on the accuracy to be obtained, when the obtained angle θx1 is large, as shown in FIG. 12B, the optical scanning unit 6 is corrected by the angle θx1, that is, the scanning direction of the optical scanning unit 6 is inclined by −θx1. If the inclination θx2 in the scanning direction of the optical scanning unit 6 with respect to the measurement lights P1 and P3 is again obtained by approaching the arrangement of the measurement lights, sufficient accuracy can be obtained. Here, the inclination of the Y axis relative to the measurement light array used for calculating the correction amount of the optical scanning unit 6 for correction is that the scanning direction is in the vicinity of the X axis, and the difference in correction amount due to the Y axis inclination is small. It may be 0 °. However, since θx1 is more realistic, it is calculated as θx1. The correction coefficient described later is a correction coefficient for the X-axis and Y-axis drive axes of the optical scanning unit 6 when the measurement light is advanced in accordance with the angle of the arrangement direction θx1, and multiplies the distance by the correction coefficient described later. The measured value may be used as the driving amount of each axis of the X axis and the Y axis when the measurement light moves the distance l. If the traveling direction of the measurement light is the positive side of the X axis, the distance takes a positive value, and if the traveling direction is the negative side of the X axis, the distance takes a negative value. At this time, when θx1 becomes a positive value, the Y-axis correction coefficient is a value obtained by multiplying the Y-axis coefficient by −1.

  That is, the control unit 23 drives the X axis of the optical scanning unit 6 again in this state and moves it to a position where there is no line sensor L between the measurement lights P1, P2, and P3. As shown in FIG. 12B, the control unit 23 drives the optical scanning unit 6 in the X direction in a state where the optical scanning unit 6 is corrected by the angle θx1 in the line sensor L direction. The control unit 23 then positions the positions P1b, P2b, and P3b on the line sensor L when the centers of the measurement lights P1, P2, and P3 pass the line sensor L, and the X-axis position P1bx of the optical scanning unit 6 at that time. , P2bx and P3bx determine the angle θx2 of the scanning axis corrected with the angle θx1. As in the case of obtaining the angle θx1, if P1b = (0, P1by); P2b = (0, P2by); P3b = (0, P3by); then the angle θx2 is obtained by the following equation.

  The positions P1B, P2B, and P3B of the measurement lights P1, P2, and P3 when the position of the optical scanning unit 6 is 0 are obtained by the following formula.

When a straight line passing through the vicinity of the positions P1B, P2B, and P3B is obtained by the least square method or the like, an inclination angle θx3 of the straight line is obtained. As a result, the angle θx of the X-axis and the inclination of the optical scanning unit 6 with respect to the measurement light array can be obtained by the following equation.
θx = θx1 + θx2−θx3

  In this embodiment, the light receiving unit 10 is configured by a one-dimensional line sensor L. However, it may be configured by a two-dimensional CCD, and a two-dimensional CCD is provided with a reference axis to measure an X-axis angle error. What is necessary is just to obtain | require the correction amount of each drive shaft. At this time, in order to obtain the center position of each measurement light, the gravity center position of the light quantity of each pixel of the two-dimensional CCD received from the measurement light to be obtained may be obtained.

  Further, when the light receiving unit 10 is constituted by a two-dimensional CCD, the optical scanning unit 6 is driven singly for each axis, and light is received by the position of the optical scanning unit at that time and the position of the measurement light measured by the light receiving unit 10. The X-axis tilt and Y-axis tilt of the optical scanning unit 6 with respect to the unit 10 are also obtained.

  As described above, by using the position of the light receiving unit 10 that receives the measurement light as a reference, the position of the measurement light array in the scanning direction of the optical scanning unit 6 and the optical scanning unit of the measurement light array obtained from the position The angle with respect to 6 can be obtained. When the obtained position is different from the design value, the center position of the measurement light array can be corrected by the optical scanning unit 6, and the measurement light can be brought close to the design value position.

  Although the measurement position is based on the coordinates of the light receiving unit 10, the mirror 9 is not on the measurement optical path, the position where the measurement light is irradiated onto the eyepiece 7b, and the mirror 9 is on the measurement optical path. The relationship with respect to the position where the measurement light is applied to the light receiving unit 10 is defined. Thereby, the coordinate system of the position of the light receiving unit 10 can be matched with the coordinate system of the eyepiece lens 7b to correct the position as coordinates on the fundus 8r.

  In the tandem scan, it is necessary to reduce the width of the measurement light with respect to the scanning direction created by each measurement light with respect to the scanning direction of the optical scanning system. For this purpose, the width of the measurement light with respect to the scanning direction can be reduced by matching the scanning direction with the optical scanning system with respect to the inclination of the measurement light array. That is, by using the X axis of the optical scanning unit 6 and the inclination angle θx of the optical scanning unit 6 with respect to the obtained measurement light array, the optical scanning unit 6 is corrected by the following equation, thereby The scanning direction can be adjusted. Accordingly, it is possible to reduce the width of the measurement light with respect to the scanning direction created by each measurement light with respect to the scanning direction of the optical scanning system.

  This correction coefficient is a correction coefficient for the X-axis and Y-axis drive axes of the optical scanning unit 6 when the measurement light is advanced in accordance with the angle of the arrangement direction θx, and is a value obtained by multiplying the distance and the correction coefficient described above. May be the driving amount of each axis of the X axis and the Y axis when the measuring light moves the distance l. If the traveling direction of the measurement light is on the positive side of the X axis, the distance takes a positive value. If the traveling direction is on the negative side of the X axis, the distance takes a negative value. At this time, the correction coefficient for the Y axis is a value obtained by multiplying the coefficient for the Y axis by −1 when θx becomes a positive value.

  As described above, the position of the measurement light, the light amount when the light receiving unit 10 detects the measurement light, and the position of the optical scanning unit 6, the position of the measurement light, the angle of the measurement light array, and the optical scanning unit The positional relationship with the scanning angle of 6 is obtained.

  From the above positional relationship, the scanning direction of the scanning unit 6 can be adjusted to the arrangement of the measurement light, so that it is not necessary to make a precise adjustment at the time of assembly, and even if a deviation due to a change in time or an impact occurs. The scanning direction of the optical scanning unit 6 with respect to the array of measurement light can be corrected. Therefore, the width of the measurement light with respect to the scanning direction created by each measurement light can be reduced. Also, by measuring the positional relationship of each measurement light, you can see the amount of deviation from the design value of each measurement light, so each light source adds the data string of the same measurement location of the measurement object by shifting the deviation image It becomes possible to average. Thereby, an optical tomographic image with a high S / N ratio can be obtained in the tandem scan.

  In this embodiment, using the line sensor L as a reference for the Y axis, the error of the inclination of each axis of the optical scanning unit 6 with respect to the array of measurement light is measured, and the correction amount of each driven object is obtained. However, as another embodiment, an error between an angle and a position with respect to the reference is measured on the basis of one of the X-axis and Y-axis of the optical scanning unit or the angle of the measurement light array, and correction of each driving unit is performed. The amount may be determined.

(Third embodiment)
Next, a third embodiment of the present invention will be described. FIG. 13 is a diagram showing a configuration of an OCT apparatus according to the third embodiment of the present invention. In the present embodiment, an imaging apparatus using a Fourier domain optical coherence tomography is taken as an example. The difference between the first embodiment and the third embodiment is that a detector 11 is provided in place of the fundus instead of the light receiving unit 10.

  Since the mirror 9 is arranged on the measurement optical path on the detection body 11, the eyepiece lens 7c is irradiated with measurement light, and a tomographic image of the detection body bottom portion 11r can be measured. This detection body 11 has a band with different tomographic thicknesses detected depending on the position where measurement light is irradiated as shown in FIG. Here, it is assumed that the measurement light array of the fiber connection portion 35 is horizontally fixed to each light source of the optical fiber 34 as shown in 35a, 35b, and 35c of FIG.

  In the third embodiment, the mirror 9 is arranged on the measurement optical path in order to measure the arrangement state of the measurement light. The light irradiated from the light source 1 passes through the sample arm 1001 and is irradiated to the detection body 11 as measurement light through the mirror 9. The irradiated measurement light is combined with reference light as return light and incident on the spectroscope 1003, and a tomographic image can be acquired.

  FIG. 14 is a diagram showing the detection body 11. As shown in FIG. 14, the detection body 11 resembles the human eye, and has a lens 11a instead of a crystalline lens. The measurement light forms an image on the detection body bottom portion 11r that is optically equivalent to the fundus oculi 8r via the lens 11a and travels toward the spectroscope 1003 as return light. The optical scanning unit 6 scans the detection body bottom portion 11r using the center of the lens 11a as a pivot. The detection body bottom portion 11r draws a spherical surface around the pivot portion in the scanning range. As a result, the scanning angle and the coordinates of the detection body bottom portion 11r are in a proportional relationship, and the positional deviation due to the error in the incident position of the measurement light is also reduced.

Further, as shown in FIG. 14, the detection body bottom portion 11r has a band in which a tomographic image is detected at the center, and the thickness of the tomographic image changes with respect to the vertical direction of the band. Thus, the vertical position of the band can be determined. The detection unit 11 is formed by crossing two orthogonal bands 11v and 11f, and the center of the horizontally extending band 11f crosses the vertically extending band 11v. Indicates that the thickness of the tomographic image changes in the vertical direction. The vertical band 11v on the coordinates is used as a reference for the Y axis, and the tomographic image is different in thickness when the position irradiated with the measuring light changes in the direction perpendicular to the band, that is, in the X axis direction. Thus, the position in the X direction irradiated can be obtained uniquely. In the horizontal band 11f, the thickness of the tomographic image changes depending on the position where the measurement light is irradiated in the Y direction, and the position in the X direction with respect to the thickness is uniquely obtained. Therefore, the position Py in the Y direction with respect to the thickness t of the band 11f beside the thickness is obtained as follows.
Py = fy (t)
Further, the vertical band 11v is obtained in the following manner as the position Px in the X direction with respect to the thickness t.
Px = fx (t)

  In the present embodiment, a belt-like shape is used for the detection body. This makes it possible to increase the difference in thickness of the tomographic image to be measured by changing the position of a small amount of measurement light, and to increase the position resolution.

  In the present embodiment, the detection body bottom 11r is a spherical surface centered on the pivot, but it may be a spherical surface such as a plane or an eyeball, and the pivot may be the position of the crystalline lens. In this case, the position of the detection body bottom 11r with respect to the scanning angle. May be corrected.

  In FIG. 14, P1, P2, and P3 are measurement lights. When the apparatus is started up and the initial drive of each device is completed, the mirror 9 is on the measurement optical path, and the detection body 11 is irradiated with measurement light, as shown in FIG. 14, the design is centered on the bands 11v and 11f. It is assumed that the center of the measurement light array coincides. The position of the optical scanning unit 6 is a position where the central measurement light is present with respect to the detection body bottom 11r, that is, light when the central measurement light irradiates the minus coordinate side on the coordinates in a design not including each error. The position of the scanning unit 6 is a minus position.

  In addition, the image rotator 2 in the present embodiment normally rotates the light passing through a half rotation, but for the convenience of explanation, the rotation amount of the light is the rotation amount of the image rotator 2. The image rotator 2 sets the angle when the measurement light is horizontal to the horizontal band 11f to 0 °, and the counterclockwise phrase to the plus direction.

  First, the control unit 23 positions the image rotator 2 at a position of 0 °, that is, the measurement light is horizontal with respect to the horizontal band 11f by design, and the inclination between the horizontal band 11f and the X-axis scanning direction of the optical scanning unit 6 is set. Then, an approximation of the inclination between the direction of the measurement light array and the X axis of the optical scanning unit 6 is obtained.

FIG. 15 is a diagram for explaining how to obtain the horizontal band 11 f of the detection body, the arrangement of the measurement light, and the inclination of the optical scanning unit 6. The image rotator 2 is at a position of 0 °. As shown in FIG. 15A, the X-axis and Y-axis of the optical scanning unit 6 are fixed at the center, and the horizontal band 11f is irradiated with measurement light. The control unit 23 measures the tomographic images of the measuring beams P1 and P3, and obtains the positions P1ay and P3ay of the measuring beams P1 and P3 in the Y direction from the thickness of the tomographic images. Here, when the positions of the measurement lights P1 and P3 on the design values are (p1ax, 0) and (p3ax, 0) θ, the approximate angle θ1 between the horizontal band 11f and the measurement lights P1 and P3 is obtained by the following equation. It is done.
sin (θ1) = (P1ay−P3ay) ÷ (p1ax−p3ax)

The inclination between the horizontal band 11 f and the X axis of the optical scanning unit 6 is obtained by driving the X axis of the optical scanning unit 6. As shown in FIG. 15B, the control unit 23 moves the X axis of the optical scanning unit 6 in the above state, for example (p3ax-p1ax), obtains a tomographic image of the measurement light P1 here, A position P1by in 13 Y directions at this time is obtained from the thickness of the image. Thereby, the inclination θx of the X axis of the horizontal band 11f and the optical scanning unit 6 is obtained by the following equation.
sin (θx) = (P1by−P1ay) ÷ (p3ax−p1ax)
Further, the approximate θ2 of the X-axis scanning direction tilt of the optical scanning unit 6 with respect to the measurement lights P1 and P3 is obtained by the following equation.
θ2 = θx−θ1

  Next, the control unit 23 obtains the inclination between the vertical band 11v and the scanning direction of the Y-axis of the optical scanning unit 6. FIG. 16 is a diagram for explaining how to obtain the inclination between the vertical band 11v and the scanning direction of the Y-axis of the optical scanning unit 6. In FIG. The control unit 23 fixes the X axis of the optical scanning unit 6 at the center, uses the measurement light P2 for the Y axis of the optical scanning unit 6, and measures a tomographic image near the PU and PD. PU is located at the upper part of the vertical band 11f, and PD is located at the lower part of the vertical band 11v, both at the center of the Y axis. Similarly to the horizontal band 11f, the vertical band 11v is perpendicular to the band, that is, in the vertical band 11v, the thickness of the tomographic image varies depending on the position where the measurement light is irradiated in the X direction. The position is obtained.

If the position of the X phrase obtained from the thickness of the tomographic image in the vicinity of PU and PD is Pux and Pdx, and the position of the Y axis of the optical scanning unit 6 when measured is Puy and Pdy, the optical scanning with respect to the vertical band 11v is performed. The angle θy in the scanning direction of the Y axis of the unit 6 is obtained by the following equation.
Sin (θy) = (Pux−Pdx) ÷ (Puy−Pdy)

  Next, the control part 23 calculates | requires the distance between measurement light P1, P2, and P3. FIG. 9 is a diagram for explaining how to obtain the distances of the measurement lights P1, P2, and P3. The control unit 23 shifts the Y axis of the optical scanning unit 6 from the center and scans the X axis of the optical scanning unit 6 so that the measurement light is not irradiated to the horizontal band 11f. It scans and moves to the position where measurement light is irradiated to the vertical band 11v of measurement light. When the optical scanning unit 6 is moved, the optical scanning unit 6 is driven while being corrected by the angles θx and θy between the bands 11f and 11v and the scanning unit 6. Then, the control unit 23 drives the optical scanning unit 6 so that the measurement lights P1, P2, and P3 are positioned on the vertical band 11v, for example, the position of Pc. That is, if the position of Pc is (0, Pcy) and the positions of the design values of the measurement lights P1, P2, and P3 are (p1ax, 0), (p2ax, 0), and (p3ax, 0), the measurement light P1 is In order to irradiate the position in the vicinity of Pc, the optical scanning unit 6 needs to be in the position of (−p1ax, Pcy) in the coordinate system of the detection body bottom portion 11r. When this is converted into the coordinate system (X1, Y1) of the optical scanning unit 6, the following equation is obtained. The control unit 23 drives the optical scanning unit 6 to the position (X1, Y1).

  In this state, the control unit 23 measures the tomographic image with the measurement light P1, and obtains the position P1dx in the X direction on the vertical band 11v from the obtained thickness tp1 of the tomographic image. Then, the control unit 23 drives the optical scanning axis by p1ax−p2ax in the direction of the approximate inclination θ1 of the measurement light obtained above from this state. That is, the control unit 23 is driven so that the measurement light P2 is on Pc. The optical scanning unit 6 is driven from the state in which the tomographic image is measured with the measurement light P1. Here, the control unit 23 measures the tomographic image with the measurement light P2, and obtains the position P2dx in the X direction on the vertical band 11v from the obtained thickness tp2.

  Similarly, the control unit 23 drives the scanning unit 6 by p2ax−p3ax in the approximate inclination θ1 direction of the measurement light so as to irradiate the position of the measurement light P3 to Pc from this state. Then, the control unit 23 measures the tomographic image with the measurement light P3, and obtains the position P3dx in the X direction on the vertical band 11v from the obtained thickness tp3 of the tomographic image.

As the distance in the direction connecting the measurement lights P1 and P3, if the distance between the measurement lights P1 and P2 is p12xl, the distance between the measurement lights P2 and P3 is p23xl, and the distance between the measurement lights P1 and P3 is p13xl, the following equation is obtained. It is done.
P12xl = p2ax−p1ax − ((p2dx−p1dx) ÷ cos θ1)
P23xl = p3ax−p2ax − ((p3dx−p2dx) ÷ cos θ1)
P13xl = p3ax−p1ax − ((p3dx−p1dx) ÷ cos θ1)

FIG. 10 is a diagram for explaining how to obtain the array of measurement light. When the tomographic image is measured by irradiating the horizontal band 11f with the measuring beams P1, P2, and P3 with the optical scanning unit 6 as the center, the thickness is obtained from the thickness of the tomogram at the position irradiated with the measuring beams P1, P2, and P3. From the positions P1ya, P2ya, and P3ya in the X direction with respect to the horizontal band 11f, the measurement lights P1, P2, and P3 have the following positional relationship with respect to the horizontal band 11f, and measurement with respect to the horizontal band 11f by the least square method or the like. The angle θf of the light arrangement is obtained.
(−P12xl × cos (θ12), P1ya), (0, P2ya), (P23xl × cos (θ23), P3ya)
Here, sin (θ12) = (P2ya−P1ya) ÷ P12xl, sin (θ23) = (P3ya−P2ya) ÷ P23xl

  As a result, the X-axis inclination θx of the optical scanning unit 6 with respect to the horizontal band 11f serving as the X coordinate reference, the Y-axis inclination θy of the optical scanning unit 6 with respect to the vertical band 11v serving as the Y-axis reference, and the X coordinate The inclination θf of the measurement light array when the image rotator 2 for the reference horizontal band 11f attempts to level the measurement light array with respect to the horizontal band 11f is obtained.

Next, the rotation center position of the image rotator 2 is obtained. FIG. 11 is a diagram for explaining how to obtain the rotation center position of the image rotator 2. The control unit 23 rotates the image rotator 2 so that the optical scanning unit 6 is at the center position and the measurement light P1 is positioned on the horizontal band 11f. Here, the control unit 23 measures the tomographic image with the measurement light P1, and obtains the position p1ly in the Y direction on the horizontal band 11f of the measurement light P1 from the thickness of the tomographic image. The controller 23 rotates the image rotator 2 180 degrees from this state. The control unit 23 measures the tomographic image of the horizontal band 11f with the measurement light P1, and obtains the position p1ry in the Y direction on the horizontal band 11f from the thickness of the tomographic image. From this state, the control unit 23 rotates the image rotator 2 so that the measurement light P1 is on the upper part of the vertical band 11v. The control unit 23 measures the tomographic image with the measurement light P1, and obtains the position p1ux in the X direction on the vertical band 11v from the thickness of the tomographic image. The controller 23 rotates the image rotator 2 180 degrees from this state. The control unit 23 measures the tomographic image of the vertical band 11v with the measurement light P1, and obtains the position p1dx in the x direction on the vertical band 11v from the thickness of the tomographic image. The rotation center position RC of the image rotator 2 is obtained by the following equation.
RC = ((p1ux + p1dx) / 2, (p1ly + p1ry) / 2)

  In the present embodiment, an image rotator 2 that is a mechanism for changing the inclination of the array of measurement light is provided. However, in the above embodiment, the image rotator 2 is driven only when the measurement light array is first leveled and when the rotation center position of the image rotator 2 is obtained. Therefore, when there is no mechanism for changing the angle of the measurement light array and the measurement light array is fixed to the horizontal band 11f, the angle of the measurement light array can be eliminated by omitting the step of obtaining the rotation center position of the image rotator 2. The inclination of the scanning axis of the optical scanning unit 6 with respect to can be obtained.

  The measurement position is based on the coordinates of the detection body bottom 11r. However, the mirror 9 is not on the measurement optical path, the measurement light is irradiated on the eyepiece 7b, and the mirror 9 is on the measurement optical path. The relationship with respect to the position where measurement light is irradiated to the detection body bottom part 11r is defined. Thereby, the coordinate system of the position of the photoreceptor bottom 11r can be matched with the coordinate system of the eyepiece 7b, and the position can be corrected as the coordinates on the fundus 8r.

  As described above, the thickness of the tomographic image to be detected varies depending on the position irradiated with the measurement light, and the detection body 11 is used in which the position is obtained with respect to the direction serving as the reference axis depending on the thickness of the tomographic image. . Thereby, the inclination of the scanning unit 6 with respect to the arrangement of the measurement light can be obtained from the position of the optical scanning unit 6 and the position on the detection body corresponding to the thickness of the tomographic image measured at that time. Since it is possible to adjust the scanning direction of the optical scanning unit 6 to the measurement light array from this inclination, it is not necessary to perform strict adjustment for adjustment at the time of assembly. The scanning direction of the optical scanning unit 6 with respect to the array of measurement light can be corrected. Therefore, the width of the measurement light with respect to the scanning direction created by each measurement light can be reduced. In addition, by measuring the positional relationship of each measurement light, it is possible to know the amount of deviation from the design value of each measurement light. By shifting the image for the deviation, each measurement light adds the data string of the same measurement location of the measurement object. It becomes possible to average. For these reasons, an optical tomographic image having a high S / N ratio can be obtained by tandem scanning.

(Fourth embodiment)
Next, a fourth embodiment according to the present invention will be described. FIG. 13B is a diagram showing a configuration of an OCT apparatus according to the fourth embodiment of the present invention. In the present embodiment, an imaging apparatus using a Fourier domain optical coherence tomography is taken as an example. The difference from the first embodiment is that a fiber connection portion 36 capable of driving the position of the measurement light is provided instead of the fiber connection portion 35 connected to the sample arm 1001. FIG. 2B is a diagram illustrating the configuration of the fiber connection portion 36 in the present embodiment, and is a view of the fiber connection portion 36 viewed from the fiber end. 36 is fixed to the sample arm 1001. The measurement light is incident on the sample arm 1001 in an array of fiber ends 35 i, 35 j, 35 k corresponding to the optical fibers 34. The positions of the fiber ends 35i, 35j, and 35k can be adjusted in the vertical and horizontal directions in FIG. 2B by the drive units 36a, 36b, and 36c, and are driven by instructions from the control unit 23. Note that the fiber ends may be configured such that their positional relationship can be independently changed in a three-dimensional direction.

  In the first embodiment, the optical scanning unit 6 and the image rotator 2 are driven, and the position of the measurement light incident on the line sensor L at that time, as shown in FIGS. 5D and 6C, Measurement light positions P1A, P2A, and P3A are obtained. In the present embodiment, the driving units 36a, 36b, and 36c are driven from the positions of the respective measurement lights, and the arrangement of the fiber ends 35i, 35j, and 35k is corrected to the design position, or the measurement light positions are linearized. By doing so, the width of the measurement light with respect to the scanning direction created by each measurement light can be suppressed to a very small range, and by these, an optical tomographic image with a high SN ratio can be obtained in tandem scanning. become. In the present embodiment, three measurement lights are taken as an example, and therefore it is not necessary that all of 36a, 36b, and 36c can be driven, and it is sufficient that at least one of them can be driven.

  In this embodiment, the fiber connection portion 35 of the first embodiment is changed to a fiber connection portion 36 that can change the arrangement position of the measurement light, but the second and third embodiments are the same. The position of the measurement light can be corrected by changing 35 to the fiber connection portion 36 that can change the arrangement position of the measurement light. In the second embodiment, the drive units 36a, 36b, and 36c are driven based on the positions P1B, P2B, and P3B of the measurement light obtained by Equation 6, and the arrangement of the fiber ends 35i, 35j, and 35k is moved to the designed position. By correcting the position or making it linear, it becomes possible to suppress the width of the measurement light with respect to the scanning direction created by each measurement light to a smaller range. In the third embodiment, the drive units 36a, 36b, and 36c are driven based on the measurement light positions P1, P2, and P3 obtained in FIG. 10, and the arrangement of the fiber ends 35i, 35j, and 35k is moved to the designed position. By correcting the position or making it linear, it becomes possible to suppress the width of the measurement light with respect to the scanning direction created by each measurement light to a smaller range.

Claims (15)

An imaging device that acquires an image of an inspection object based on a plurality of return lights from the inspection object irradiated with a plurality of measurement lights,
Scanning means for scanning the plurality of measurement lights;
Detecting means for detecting an array of the plurality of measurement lights in the inspection object;
An arrangement adjusting means for adjusting the arrangement in the scanning direction of the scanning means based on the detection result of the detecting means;
An imaging device comprising:   The imaging apparatus according to claim 1, wherein the arrangement adjusting unit adjusts the position of the arrangement based on the scanning direction and the acquired angle. A dividing unit that divides the plurality of measurement lights into an optical path of the detection unit;
Control means for removing the dividing means from the optical path after adjusting the angle of the arrangement by the arrangement adjusting means;
The imaging apparatus according to claim 2, further comprising:   The imaging apparatus according to claim 1, further comprising a calculation unit that calculates an angle of the array with respect to a scanning direction of the scanning unit based on a detection result of the detection unit.   5. The imaging apparatus according to claim 1, wherein the detection unit detects an irradiation position of the plurality of measurement lights on the inspection object.   And a tomographic image acquisition unit configured to acquire a tomographic image of the object to be inspected based on a plurality of combined lights obtained by combining the plurality of return lights and a plurality of reference lights corresponding to the plurality of measurement lights, respectively. The imaging apparatus according to any one of claims 1 to 5, wherein   Based on the positions of the plurality of measurement lights detected by the detection means, the positions of the arrangement adjustment means, and the positions of the scanning means, the positions of the plurality of measurement lights and the arrangement of the plurality of measurement lights The imaging apparatus according to claim 1, further comprising a calculating unit that calculates a relationship between the angle of the scanning and a scanning angle of the scanning unit.   The imaging apparatus according to claim 7, wherein the detection unit detects positions of the plurality of measurement lights in a one-dimensional direction.   Based on the positions of the plurality of measurement lights detected by the detection means and the positions of the scanning means, the positions of the plurality of measurement lights, the angles of the arrangement of the plurality of measurement lights, and the scanning means The imaging apparatus according to claim 1, further comprising calculation means for calculating a relationship with the scanning angle.   The detection means detects the positions of the plurality of measurement lights in a one-dimensional direction, and the relationship between the positions of the plurality of measurement lights, the angle of the arrangement of the plurality of measurement lights, and the scanning angle of the scanning means The imaging apparatus according to claim 9, wherein is an angle of an array of the plurality of measurement lights with respect to a scanning axis of the scanning unit. A plurality of lights emitted from the light source are branched into measurement light and reference light, respectively, and the measurement light is guided to the inspection object and the reference light is guided to the reference mirror, and the return light from the inspection object and the reference mirror An imaging device for capturing a tomographic image of the inspection object based on the reflected light of
An adjusting means for adjusting the angle of the arrangement of a plurality of measurement lights arranged on a straight line;
A scanning unit that scans the plurality of measurement light beams whose array angles are adjusted by the adjusting unit;
A measuring means for measuring a tomographic image of a detection body that is disposed at a position optically corresponding to the object to be inspected by driving the adjusting means and the scanning means;
Measuring means for measuring the positions of the plurality of measuring lights from the thickness of the tomographic image of the detection body measured by the measuring means;
Based on the positions of the plurality of measurement lights measured by the measurement means, the positions of the adjustment means, and the positions of the scanning means, the positions of the plurality of measurement lights and the arrangement of the plurality of measurement lights An imaging apparatus comprising: a calculating unit that calculates a relationship between an angle and a scanning angle of the scanning unit. A plurality of lights emitted from the light source are branched into measurement light and reference light, respectively, and the measurement light is guided to the inspection object and the reference light is guided to the reference mirror, and the return light from the inspection object and the reference mirror An imaging device for capturing a tomographic image of the inspection object based on the reflected light of
Scanning means for scanning a plurality of measurement lights arranged on a straight line;
Measuring means for measuring a tomographic image of a detection body that is disposed at a position optically corresponding to the object to be inspected by driving the scanning means, and capable of measuring a tomographic image;
Measuring means for measuring the positions of the plurality of measuring lights from the thickness of the tomographic image of the detection body measured by the measuring means;
Based on the positions of the plurality of measurement lights measured by the measurement means and the positions of the scanning means, the positions of the plurality of measurement lights, the angles of the plurality of measurement lights, and the scanning angles of the scanning means An imaging apparatus comprising: a calculating unit that calculates a relationship between   The thickness of the tomographic image that is measured differs depending on the position where the plurality of measurement lights are irradiated, and the position where the plurality of measurement lights are irradiated is uniquely determined by the thickness of the measured tomographic image. The imaging apparatus according to claim 12, wherein the tomographic structure is defined by two orthogonal axes.   The imaging apparatus according to claim 13, further comprising a correction unit that corrects a driving amount of the scanning unit based on a deviation of a scanning axis of the scanning unit with respect to the angles of the plurality of measurement light beams.   15. The method according to claim 13, further comprising selection means for selecting tomographic image data that are measured at the same position by the plurality of measurement lights based on the positions of the plurality of measurement lights and are averaged. The imaging device described.

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